Treatment system response to transient AOX (adsorbable organic halogen) loadings

If promulgated as proposed, effluent guidelines for the U.S. pulp and paper industry will impose average monthly and maximum daily numerical limits of discharged AOX (adsorbable organic halogen). At this time, it is unclear whether the maximum-day variability factor used to establish the proposed effluent guidelines will provide sufficient margin for mills to achieve compliance during periods of normal but variable operating conditions within the pulping and bleaching processes. Consequently, additional information is needed to relate transient AOX loadings with final AOX discharges. This paper presents a simplistic dynamic model of AOX decay during treatment. The model consists of hydraulic characterization of an activated sludge process and a first-order decay coefficient for AOX removal. Data for model development were acquired by frequent collection of influent and effluent samples at a bleach kraft mill during a bleach plant shutdown and startup sequence.

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Surface characterization of paper and paperboard using a stylus contact method

Nordic Pulp & Paper Research Journal ◽

10.1515/npprj-2019-0005 ◽

2020 ◽

Vol 35 (1) ◽

pp. 78-88

Author(s):

Young Chan Ko ◽

Lili Melani ◽

Na Young Park ◽

Hyoung Jin Kim

Keyword(s):

Surface Roughness ◽

Surface Characterization ◽

Paper Industry ◽

Surface Friction ◽

Operating Conditions ◽

Contact Method ◽

Measuring Surface ◽

Two Samples ◽

Friction Measurements

AbstractSurface characterization is important and has many applications in the paper industry. Surface characterization requires both surface roughness and surface friction. The relationship between the two has not been fully established for paper and paperboard. It has been a common practice that only the average property and the standard deviation with the coefficient of variation (COV) are reported for surface roughness and friction measurements. This practice, however, provides few information on surface structure and can lead to wrong judgments because two samples having the same average and the COV can have different physical properties. To avoid such mistake, a new surface characterization method has been developed. To this end, surface roughness- and friction-profiles have been obtained using a latest version of Kawabata surface tester (Model: KES-SESRU, Kato Tech, Kyoto Japan). This new version uses the same stylus for both measuring surface roughness and friction under the same operating conditions. It was found that a correlation between the surface roughness and surface friction was very low. This indicates that they should be independent of each other. Therefore, both should be determined for surface characterization.

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Model development of integrated CPOx reformer and SOFC stack system

Polish Journal of Chemical Technology ◽

10.1515/pjct-2016-0069 ◽

2016 ◽

Vol 18 (4) ◽

pp. 41-46 ◽

Cited By ~ 1

Author(s):

Paulina Pianko-Oprych ◽

Seyed Mehdi Hosseini ◽

Zdzislaw Jaworski

Keyword(s):

Steady State ◽

Model Development ◽

Dynamic Modelling ◽

Integrated System ◽

Operating Conditions ◽

System Response ◽

Dynamic Mode ◽

Valuable Insight ◽

Steady State Mode ◽

Load Variations

Abstract The main purpose of this study was to develop a mathematical model, in a steady state and dynamic mode, of a Catalytic Partial Oxidation (CPOx) reformer – Solid Oxide Fuel Cell (SOFC) stack integrated system in order to assess the system performance. Mass balance equations were written for each component in the system together with energy equation and implemented into the MATLAB Simulink simulation tool. Temperature, gas concentrations, pressure and current density were computed in the steady-state mode and validated against experimental data. The calculated I–V curve matched well the experimental one. In the dynamic modelling, several different conditions including step changes in fuel flow rates, stack voltage as well as temperature values were applied to estimate the system response against the load variations. Results provide valuable insight into the operating conditions that have to be achieved to ensure efficient CPOx performance for fuel processing for the SOFC stack applications.

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AOX Removal from Bleached Kraft Mill Wastewater: A Comparison of Three Biological Treatment Processes

Water Science & Technology ◽

10.2166/wst.1992.0418 ◽

1992 ◽

Vol 26 (1-2) ◽

pp. 387-396 ◽

Cited By ~ 4

Author(s):

E. R. Hall ◽

W. G. Randle

Keyword(s):

Biological Treatment ◽

Operating Conditions ◽

Gas Stripping ◽

Treatment Processes ◽

Organic Halogen ◽

System Data ◽

Kraft Mill ◽

Removal Efficiencies ◽

Comparison Of The Results ◽

Aox Removal

Laboratory scale activated sludge (AS), facultative stabilization basin (FSB) and aerated stabilization basin (ASB) processes were operated under controlled parallel conditions to assess the AOX (adsorbable organic halogen) removal efficiencies attainable in each. A comparison of the results obtained under a variety of operating conditions indicated that higher removal efficiencies of total and filterable AOX were achieved in the FSB and ASB processes than in the AS system. Data are also presented to indicate the extent to which influent AOX was removed by biodegradation, biosorption and off-gas stripping.

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CHARACTERIZATION OF NOZZLE EROSION BEHAVIOR UNDER ROCKET MOTOR OPERATING CONDITIONS

International Journal of Energetic Materials and Chemical Propulsion ◽

10.1615/intjenergeticmaterialschemprop.2011001444 ◽

2010 ◽

Vol 9 (6) ◽

pp. 533-548

Author(s):

Brian Evans ◽

Kenneth K. Kuo ◽

Andrew C. Cortopassi

Keyword(s):

Rocket Motor ◽

Operating Conditions ◽

Erosion Behavior ◽

Nozzle Erosion

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Investigations of Road Wear Caused by Studded Tires

Tire Science and Technology ◽

10.2346/tire.14.420101 ◽

2014 ◽

Vol 42 (1) ◽

pp. 2-15

Author(s):

Johannes Gültlinger ◽

Frank Gauterin ◽

Christian Brandau ◽

Jan Schlittenhard ◽

Burkhard Wies

Keyword(s):

Traffic Safety ◽

Test Bench ◽

Operating Conditions ◽

Test Method ◽

Analytical Models ◽

The Road ◽

Driving Speed ◽

Major Factors ◽

Tire Friction ◽

Variable Operating Conditions

ABSTRACT The use of studded tires has been a subject of controversy from the time they came into market. While studded tires contribute to traffic safety under severe winter conditions by increasing tire friction on icy roads, they also cause damage to the road surface when running on bare roads. Consequently, one of the main challenges in studded tire development is to reduce road wear while still ensuring a good grip on ice. Therefore, a research project was initiated to gain understanding about the mechanisms and influencing parameters involved in road wear by studded tires. A test method using the institute's internal drum test bench was developed. Furthermore, mechanisms causing road wear by studded tires were derived from basic analytical models. These mechanisms were used to identify the main parameters influencing road wear by studded tires. Using experimental results obtained with the test method developed, the expected influences were verified. Vehicle driving speed and stud mass were found to be major factors influencing road wear. This can be explained by the stud impact as a dominant mechanism. By means of the test method presented, quantified and comparable data for road wear caused by studded tires under controllable conditions can be obtained. The mechanisms allow predicting the influence of tire construction and variable operating conditions on road wear.

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Performance evaluation and boron rejection in a SWRO system under variable operating conditions

Computers & Chemical Engineering ◽

10.1016/j.compchemeng.2021.107441 ◽

2021 ◽

pp. 107441

Author(s):

A. Ruiz-García ◽

I. Nuez

Keyword(s):

Performance Evaluation ◽

Operating Conditions ◽

Variable Operating Conditions

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Critical Review of EMC Standards for the Measurement of Radiated Electromagnetic Emissions from Transit Line and Rolling Stock

Energies ◽

10.3390/en14030759 ◽

2021 ◽

Vol 14 (3) ◽

pp. 759

Author(s):

Andrea Mariscotti

Keyword(s):

Time Distribution ◽

Communication Systems ◽

Electromagnetic Compatibility ◽

Transportation Systems ◽

Operating Conditions ◽

Rolling Stock ◽

Intrinsic Variability ◽

Statistical Characterization ◽

Electromagnetic Emissions

Accurate and comprehensive methods for the assessment of radiated electromagnetic emissions in modern electric transportation systems are a necessity. The characteristics and susceptibility of modern victim signaling and communication radio services, operating within and outside the right-of-way, require an update of the measurement methods integrating or replacing the swept frequency technique with time domain approaches. Applicable standards are the EN 50121 (equivalent to the IEC 62236) and Urban Mass Transport Association (UMTA) with additional specifications from project contracts. This work discusses the standardized methods and settings, and the representative operating conditions, highlighting areas where improvements are possible and opportune (statistical characterization of measurement results, identification and distinction of emissions and line resonances, and narrowband and broadband phenomena). In particular for the Electromagnetic Compatibility (EMC) assessment with new Digital Communication Systems, the characterization of time distribution of spectral properties is discussed, e.g., by means of Amplitude Probability Distribution and including time distribution information. The problem of determination of site and setup uncertainty and repeatability is also discussed, observing on one hand the lack of clear indications in standards and, on the other hand, the non-ideality and intrinsic variability of measurement conditions (e.g., rolling stock operating conditions, synchronization issues, and electric arc intermittence).

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Stability of Ring-Type MEMS Gyroscopes Subjected to Stochastic Angular Speed Fluctuation

Journal of Vibration and Acoustics ◽

10.1115/1.4036452 ◽

2017 ◽

Vol 139 (4) ◽

Cited By ~ 4

Author(s):

Samuel F. Asokanthan ◽

Soroush Arghavan ◽

Mohamed Bognash

Keyword(s):

Angular Velocity ◽

Degrees Of Freedom ◽

Microelectromechanical Systems ◽

Damping Ratio ◽

Operating Conditions ◽

System Stability ◽

System Response ◽

Ring Type ◽

Mems Gyroscopes ◽

The Stability

Effect of stochastic fluctuations in angular velocity on the stability of two degrees-of-freedom ring-type microelectromechanical systems (MEMS) gyroscopes is investigated. The governing stochastic differential equations (SDEs) are discretized using the higher-order Milstein scheme in order to numerically predict the system response assuming the fluctuations to be white noise. Simulations via Euler scheme as well as a measure of largest Lyapunov exponents (LLEs) are employed for validation purposes due to lack of similar analytical or experimental data. The response of the gyroscope under different noise fluctuation magnitudes has been computed to ascertain the stability behavior of the system. External noise that affect the gyroscope dynamic behavior typically results from environment factors and the nature of the system operation can be exerted on the system at any frequency range depending on the source. Hence, a parametric study is performed to assess the noise intensity stability threshold for a number of damping ratio values. The stability investigation predicts the form of threshold fluctuation intensity dependence on damping ratio. Under typical gyroscope operating conditions, nominal input angular velocity magnitude and mass mismatch appear to have minimal influence on system stability.

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Feasibility of High Speed Furnace Drawing of Optical Fibers

Journal of Heat Transfer ◽

10.1115/1.1795246 ◽

2004 ◽

Vol 126 (5) ◽

pp. 852-857 ◽

Cited By ~ 7

Author(s):

Xu Cheng ◽

Yogesh Jaluria

Keyword(s):

Optical Fibers ◽

High Speed ◽

Flow Instability ◽

Fiber Quality ◽

Domain Boundary ◽

Operating Conditions ◽

Furnace Temperature ◽

Fiber Drawing ◽

Heated Zone ◽

Additional Information

The domain of operating conditions, in which the optical fiber-drawing process is successful, is an important consideration. Such a domain is mainly determined by the stresses acting on the fiber and by the stability of the process. This paper considers an electrical resistance furnace for fiber drawing and examines conditions for process feasibility. In actual practice, it is known that only certain ranges of furnace temperature and draw speed lead to successful fiber drawing. The results obtained here show that the length of the heated zone and the furnace temperature distribution are other important parameters that can be varied to obtain a feasible process. Physical behavior close to the boundary of the feasible domain is also studied. It is found that the iterative scheme for neck-down profile determination diverges rapidly when the draw temperature is lower than that at the acceptable domain boundary due to the lack of material flow. However, the divergence rate becomes much smaller as the temperature is brought close to the domain boundary. Additional information on the profile determination as one approaches the acceptable region is obtained. It is found that it is computationally expensive and time-consuming to locate the exact boundary of the feasible drawing domain. From the results obtained, along with practical considerations of material rupture, defect concentration, and flow instability, an optimum design of a fiber-drawing system can be obtained for the best fiber quality.

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